No abstract

IrO x +RhO x mixed oxide layers on a Ti support were prepared by thermal decomposition at 450°C over the whole composition range. The temperature range 450-600°C was explored for the composition 30 mol% RhO x . Samples were characterized by means of SEM, XPS, cyclic voltammetry and polarization curves. Their electrocatalytic properties were tested for the H 2 evolution reaction. The following experimental parameters were scrutinized: voltammetric charge, Tafel slope, reaction order (H + ), electrical resistance of electrocatalysts. The electrocatalytic properties were evaluated at constant potential as a function of temperature as well as of composition. The electrode stability was assessed by comparing CV curves before and after groups of experiments. A reaction mechanism has been proposed. RhO x is more active than IrO x , its effect showing up for compositions >30 mol%.